On the Approximation of MIMO Shannon Capacity Over Spatially Correlated Ricean Fading Channels

Due to mathematical intractability, there have been only few analytical results on Ricean capacity with multiple antennas, especially for fading channels with spatial correlation. Based on a result from multivariate statistical theory, this paper shows that the statistically performance analysis for single-sided spatially correlated multiple-input multiple output (MIMO) Ricean fading channels can be replaced approximately by the corresponding analysis for single-sided correlated MIMO Rayleigh channels. In particular, an approximation closed-form expression for the Shannon capacity of single-sided correlated Ricean MIMO channels is given. It is shown by simulation that the approximation to the MIMO Shannon capacity is very accurate even for a small number of antenna elements, various correlation conditions, a wide range of Ricean K-factors, and low to high transmitting signal-to-noise ratio values. Based on the simulation results, it is guessed that the approximation is a lower bound on the MIMO Shannon capacity.